扩散张量成像在颈椎管狭窄中的应用初探

目的应用扩散张量成像(DTI)评价颈椎管狭窄对颈髓白质纤维表观扩散系数(ADC)及各向异性分数(FA)值等定量参数变化的影响。方法连续收集126例因颈肩部疼痛、感觉异常及运动功能减退等症状而行颈椎MRI检查的病人,同时纳入34名年龄条件匹配,无颈肩部不适的正常志愿者。根据颈椎管狭窄程度将病人分为3组,其中1度组82例、2度组36例、3度组8例,正常志愿者为0度组,进一步将所有受试者分为无脊髓受压组(0度组+1度组)及脊髓受压组(2度组+3度组)。所有受试者均行常规矢状面及横断面T2WI扫描,同时行DTI序列扫描。分别比较受试者各兴趣区(ROI)的FA及ADC值。结果4组间各ROI的FA值无明显差异,而ADC值除右后区ROI(F=1.56,P=0.20)外,其余5个ROI区的差异均有统计学意义(均P0.05)。2度组右前和左前区ROI的ADC值均高于0度组和1度组(均P0.05);2度组与3度组各ROI的ADC值间差异均无统计学意义(均P0.05)。3度组各个ROI的ADC值均高于0度组和1度组(P0.05)。除右后区ROI外,其余各区脊髓受压组的ADC值明显大于无脊髓受压组。结论 DTI可对颈椎管狭窄病人的颈髓进行定量研究,颈髓受压早期,白质区的ADC值升高而FA值无明显变化。

Preliminary study on using diffusion tensor imaging in evaluation of cervical stenosis

Objective To evaluate the effects of cervical stenosis on the diffusion tensor imaging derived parameters (apparent diffusion coefficient and fractional anisotropy, ADC and FA) at the white matters in cervical cord. Methods Consecutive 126 patients with pain in cervical and shoulder, parenthesis and dysfunction of movement in the upper limbs underwent cervical MR scan. Thirty-four cases aged matched volunteers having no discomfort of cervical spine and shoulder were enrolled as control group. Imaging protocol included sagittal and transverse T2 weighed imaging and diffusion tensor imaging. First we classified severity of cervical stenosis into 0° for volunteers and 1° to 3° for patients. Then we simplified the classification into compression and uncompression groups based on if presence of spinal cord compression. Eighty-two patients with 1° cervical stenosis, thirty-six patients with 2° stenosis and eight patients with 3° stenosis. The values of ADC and FA were compared among the four groups. Results The FA values didn’t significantly differ among the four groups. But the ADC values of all the regions of interest significantly differed among the four groups (P<0.05), with a single exception at the right posterior portion (F=1.56,P=0.20). In the group 2°, the ADC values at right anterior-and left anterior regions were significantly higher than that of group 0° and 1°(P<0.05). The ADC values had no differences between the 2° and 3° groups (P>0.05). In the group 3°, the ADC values were significantly higher than that of group 0° and 1° at all the regions of interest (P<0.05). With exception at the right posterior portion, the ADC values in the compression group were higher than in the uncompression group. Conclusions DTI can quantitatively evaluate the cervical cord in patients of cervical stenosis. In the early stage of compression of the cervical cord, the ADC values increase in the white matter and FA values remain unchanged.